The following is a list of costs incurred by apparel company: Fabric used during production Salaries of distribution center personnel Office janitorial supplies Repairs and maintenance costs for sewing machines Depreciation on office equipment Advertising expenses Travel costs for salespersons Utility costs for office building Depreciation on sewing machines Thread used in sewing fabric Corporate controller's salary Property taxes on factory building and equipment Research and development costs Sales commissions Oil used to lubricate sewing machines Office supervisors' salaries Wages of sewing machine operators Salary of production quality control supervisor Classify each of the costs above as either a product cost or a period costs